Immutant Feature Demo

An app showing trivial examples of all the Immutant libraries. Most log something to stdout, but the demo.web examples are available at http://localhost:8080/.

You can view a running example here: https://immutant-feature-demo.herokuapp.com/index.html.

You need at least Java 7 and Leiningen 2.4.0

You can run the app in several ways:

• With lein run
• At a repl
• From a jar
• In WildFly
  • In a cluster
• On Heroku
• On OpenShift
  • In a WildFly cluster

With lein run

The value of :main in project.clj is demo.core, which runs -main for all of the demo namespaces.

lein run

You can use the -m option to run specific namespaces, e.g.

lein run -m demo.web

At a repl

You can fire up a repl and invoke each namespace directly

lein repl

Once at a prompt, try (demo.web/-main)

From a jar

Create an uberjar and run it

lein uberjar
java -jar target/demo-standalone.jar

In WildFly

WildFly is installed by downloading and unpacking an archive. For our purposes, we'll drop it in the project directory. For a list of available versions, see http://wildfly.org/downloads/

VERSION=9.0.0.Final

# Install WildFly
wget http://download.jboss.org/wildfly/$VERSION/wildfly-$VERSION.zip
unzip wildfly-$VERSION.zip

# Create the war file and deploy it to WildFly
lein immutant war -o wildfly-$VERSION

# Fire up WildFly
wildfly-$VERSION/bin/standalone.sh -c standalone-full.xml

Note the web examples will be deployed with a context path of /demo on WildFly so go to http://localhost:8080/demo/ to see the web examples. Alternatively, to mount the app at the root context, http://localhost:8080/, rename the war file beneath wildfly-$VERSION/standalone/deployments/ to ROOT.war.

In a WildFly cluster

We'll simulate a cluster by "installing" another WildFly instance:

cp -R wildfly-$VERSION wildfly-too
rm -rf wildfly-too/standalone/data/

Because we already deployed the war file, it gets copied over, too. And to avoid spurious errors, we remove the standalone/data directory where WildFly keeps some runtime state.

Now we'll start our first instance:

wildfly-$VERSION/bin/standalone.sh -c standalone-full-ha.xml -Djboss.node.name=one -Djboss.messaging.cluster.password=demo

Note the following:

• We use the standalone-full-ha.xml file in which clustering is configured
• Since both of our peers will be on the same host, we need to give each node a unique name
• The cluster requires a password

In another shell, we fire up the second instance with similar options plus a system property to avoid port conflicts, since we're on the same host.

wildfly-too/bin/standalone.sh -c standalone-full-ha.xml -Djboss.node.name=two -Djboss.messaging.cluster.password=demo -Djboss.socket.binding.port-offset=100

You can correlate the output from both peers to the code beneath src/demo to observe HA singleton jobs, load-balanced messaging, and distributed caching. And you can observe session replication by reloading the following pages in your browser:

• http://localhost:8080/demo/counter
• http://localhost:8180/demo/counter

On Heroku

Press this button:

Or do it manually. Heroku requires a Procfile in the project root to bootstrap the app. With this in place, we simply create the heroku repo and push:

heroku create
git push heroku master

To see the log output:

heroku logs --tail

And to open the app in the browser:

heroku open

On OpenShift

The app includes start and stop action hooks beneath the .openshift/ directory that enable it to be deployed on OpenShift using the DIY cartridge.

We'll call our application demo:

rhc app-create demo diy --from-code https://github.com/immutant/feature-demo

To see the log output:

cd demo
rhc tail

Once the app is up, visit http://demo-<YOUR_DOMAIN>.rhcloud.com:8000/. The port, 8000, is optional for all but the WebSocket example, because OpenShift only supports WebSockets on port 8000.

In a WildFly cluster on OpenShift

We can use the WildFly cartridge to create a scaled application named wf. The pre_deploy_wildfly action hook will create our war file in a directory monitored by the app server.

rhc app-create wf wildfly --scaling --gear-size medium --from-code https://github.com/immutant/feature-demo

Note we set the --scaling option and a medium --gear-size. It will take a few minutes for the command to complete. Once it does, monitor the log output:

cd wf
rhc tail

View the web examples at http://wf-<YOUR_DOMAIN>.rhcloud.com:8000/

Try scaling the app up to 2 gears:

rhc cartridge-scale wildfly 2

View the gears for your app to obtain their ssh URL's:

rhc app-show --gears

Login to a gear to monitor/control it:

rhc ssh
help
gear restart
tail_all